Many building structures, particularly residential homes, include an upper portion that overlies and is supported upon a lower portion. The upper portion may include, for example, one or more floors, several load-bearing walls, and a roof. The lower portion is often a foundation that is substantially below ground. Sometimes the foundation is in turn supported upon a plurality of caissons that extend below the foundation. In this situation, the floors, load-bearing walls, roof and foundation can be considered the upper portion of the building structure and the caissons the lower portion.
Regardless of the situation, expansive soils, such as Bentonite, can cause movement of the foundation that in turn can cause the upper portion of the building to tilt. When the upper portion tilts from a level condition, substantial structural damage can occur. For example, tilting of the upper portion can result in rising or falling floors, cracked ceilings and walls, and other damage. Such damage can be avoided by supporting and maintaining the upper portion of the building structure in a level condition.
The upper portion may be maintained in a level condition through the use of support jacks that support the upper portion over the lower portion and which are individually adjustable in height. However, an indication of whether the upper portion is level is necessary in order to determine if the support jacks are properly adjusted. Consequently, a need exists for a system and method for supporting and maintaining the upper portion of a building structure in a level condition that combines adjustable support jacks with indicators that indicate whether the upper portion is level.
While a system and method that meets the above need is sufficient, there are two drawbacks associated with using support jacks to keep the upper portion level. First, if one or more of the support jacks moves in a lateral direction, the effectiveness of the system and method can be compromised. Thus, restricting lateral movement of the support jacks is desirable. Second, because the support jacks apply force to the upper portion at specific locations, the upper portion may sag between the support jacks resulting in the same type of structural damage caused by tilting of the upper portion. Consequently, it is also desirable to rigidify the upper portion to minimize sagging between the support jacks.
One further drawback associated with using support jacks to keep the upper portion level is that the support jacks need to be adjusted as the foundation moves in order to keep the upper portion level. While it is possible to adjust the support jacks by eye, doing so can be cumbersome and difficult, particularly where there are numerous support jacks or the foundation moves often. Also, if the upper portion tilts enough between adjustments, structural damage may result before the upper portion is returned to level. For these reasons, it would be desirable if it were possible to easily adjust, preferably automatically adjust, the height of the support jacks so that the upper portion is easily returned to a level condition or better yet maintained level at all times.